多浆旱生植物霸王18SrRNA基因的克隆及序列分析

摘要

In order to reveal the relationship between succulent xerophyte Zygophyllum xanthoxylum and other plants and to provide evidences for the biologically evolution, total DNA was extracted from leaves of Z. xanthoxylurn seedlings, and the 18S rRNA gene was cloned by PCR using general primers and cloned into pGEM-T vector. The positive clone identified by PCR was sequenced. The sequencing result revealed that the 18S rRNA gene fragment from Z. xanthoxylum contains 1808 bp. Homology comparison with other plants 18S rRNA gene sequences in the GenBank showed that it shared over 96% nucleotide sequence homology, so it is concluded that 18S rRNA is very conservative gene in plants. However, Homology matrix and Blast showed that Z. xanthoxylurn shared high similarity （98%） with the identified 18S rRNA in Galearia fili formis , Cnidoscolus aconiti folius and Hevea brasiliensis. Phylogenetic tree analysis indicated that Z. xanthoxylum and Panax notoginseng were most consanguineously grouped.%为探讨多浆旱生植物霸王（Zygophyllum xanthoxylum）的生物进化历程及与其他植物的亲缘关系，本研究以霸王叶基因组DNA为模板，使用通用引物扩增其18SrRNA基因片段，并克隆到pGEM—T载体，阳性克隆经鉴定后进行测序。核苷酸序列分析结果表明，该片段长1808bp，所得序列与GenBank中注册的18SrRNA基因序列的同源性均在96％以上。可见，高等植物18SrRNA的基因非常保守。同源性分析与Blast比较结果表明，霸王与小盘木（Galearia filiformis）、驱虫苋（Cnidoscolus aconitifolius）及橡胶树（Herera brasiliensis）同源性最高。系统进化树分析表明，霸王与三七（Panax notoginseng）的亲缘关系最近。